


Kinktober 2020 - DAY 5: Double Penetration in Two Holes (Bad Sans Poly/Blue, NSFW)

by yastaghr



Series: Yastaghr's Kinktober 2020 [5]
Category: Undertale (Video Game)
Genre: Alpha/Beta/Omega Dynamics, Alternate Universe - Crosstale | XTale (Undertale), Alternate Universe - Horrortale (Undertale), Alternate Universe - Underswap (Undertale), Anal Sex, Breast Fucking, Caring Dreamtale Nightmare Sans (Undertale), Crosstale Sans (Undertale), Dreamtale Nightmare Sans (Undertale), Ecto-Body (Undertale), Ecto-Breasts (Undertale), Ecto-Genitalia (Undertale), Ecto-Penis (Undertale), Ecto-Vagina (Undertale), Horrortale Sans (Undertale), Killer Sans (Undertale) - Freeform, Knotting, M/M, Mating Cycles/In Heat, Multi, Nightmares gang, Oral Knotting, Oral Sex, Pack Bonding, Pack Dynamics, Penis In Vagina Sex, Puns & Word Play, Sanscest - Freeform, Underswap Sans (Undertale), bad sans poly - Freeform, slayer sans - Freeform
Language: English
Status: Completed
Published: 2020-10-05
Updated: 2020-10-05
Packaged: 2021-03-08 02:34:03
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,802
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26838286
Author URL: https://archiveofourown.org/users/yastaghr/pseuds/yastaghr
Summary: Blue, an Omega, is thoroughly welcomed and claimed by his new pack, the Bad Sanses.(( Note: this is a continuation of https://archiveofourown.org/works/20851682/chapters/53063083 ))
Relationships: Sans/Sans (Undertale)
Series: Yastaghr's Kinktober 2020 [5]
Series URL: https://archiveofourown.org/series/1947772
Comments: 8
Kudos: 123





	Kinktober 2020 - DAY 5: Double Penetration in Two Holes (Bad Sans Poly/Blue, NSFW)

**Author's Note:**

  * Inspired by [Yastaghr's Kinktober 2019](https://archiveofourown.org/works/20851682) by [yastaghr](https://archiveofourown.org/users/yastaghr/pseuds/yastaghr). 



> I'm still on Hiatus for all my other works because I'm waiting on insurance approval for a new pain med and can't fill the old one because of conflicts :(

Blue felt sore in a very pleasant way that he hadn’t realized he had missed. Not everyone who had used him in the past had hurt him physically to do it. Mentally, yes, always. Why wouldn’t being used sexually and then discarded like a wet tissue hurt? Especially for an Omega like Blue, who was designed to be someone’s mate and the mother of their pack. Being treated like he was only worth complimenting to get into his pants had trained him to think he wasn’t worth it. But this past week Nightmare had done everything imaginable to prove that wrong. 

Some things had come up that Nightmare was surprised and pleased to learn, as he had happily shown Blue. Learning that Blue was not only trained as a healer, but also fully trained as a Doctor to the standards of most of the Multiverse and only didn’t have his license because of his Queen’s prejudices? That had made Nightmare excited. He’d shown Blue the wounds he hid under his goop and purred as his new mate healed them. Then he had found out, when Blue had tried to clean up after himself, that Blue had problems with stress and cleaning. Nightmare had been more than happy to show him that he (and, he reassured, the rest of his pack) would happily do the cleaning. 

Even without them there to speak for themselves, Nightmare had made sure to brag about all of his pack. Blue had fallen in love with Horror’s cooking when he’d had it. He’d loved Killer’s quilts and Cross’ handmade soaps. Slayer’s handmade clothes had Blue purring. He’d said they all felt so much better than the stuff Ink made. When asked, Blue had quietly explained that it never felt real enough, even though he knew it was.

That had brought Nightmare to the subject of the Star Sanses. Blue had burst into tears when Nightmare had told him he could still work with them. They were his first friends who hadn’t used him for sex, and he didn’t want to betray them. Night explained that, for the pack, playing with the Star Sanses was more of a game now. They knew that anything they did would get erased by a RESET, and they only went to worlds still having them so they could keep the balance and Nightmare maintained. That had led to the biggest surprise for Nightmare; Blue was the one who remembered RESETs, not Stretch. Blue said it was because he had “volunteered” to be Dr. Riverperson’s test subject if it meant the other would let his little brother work with him unmolested. It had worked.

Blue had found that Nightmare insisted on making some promises to him. He’d promised to take care of Blue’s father, especially when he found out that Swapster was a good dad and a good person. He’d also promised that he’d always get to choose whether he had sex now, that he could eat and drink as much of whatever he wanted as he wanted, that he’d never have to go back to his universe if he didn’t want to, and that he’d be respected from now on like he always should have been.

Being respected apparently also meant being carried if he wanted it. Blue felt a little thrill as he was being carried to the living room by Nightmare. His mate was huge compared to him, so Blue felt taller than he ever had. It made him feel special when they entered the room and he came face to face with his new pack.

“Boys,” Nightmare purred, his voice growing more excited as he went on, “You all know Blue. You all have crushes. He’s agreed to be our pack Omega! No empty compliments for now - complimenting his skills is fine, just not his appearance. Treat him good or you’ll answer to me.”

The pack, who were all sitting around the room, reacted with eagerness and something else different in each of them. Slayer, who was dressed in a frog shirt Blue had never seen before, looked so happy he was glowing. Killer’s soul had morphed into a heart, but he looked like he couldn’t believe he was this lucky, which was more emotion than Blue had ever seen in him. Horror was salivating and blushing, but Blue could hear his whispers, and he was already planning the first meal he would make for Blue. Finally, Cross looked... relieved? Then again, he was a Beta, so he was probably used to playing Omega for everyone else.

Blue looked up at Nightmare in confusion, asking, “Crushes… on me?”

Nightmare kissed him on the teeth without pressing with his tongue for entrance. “Yes, little Blue, we all do. If you’re up for it I’m sure they’d love to show it to you like I already have.”

Blue scanned their faces. They all still looked eager, and Blue wanted to cement the only bond he had ever been offered fully. He was sore, but not enough to deter his heat. “... Yes. Yes, please. If… that’s alright?”

Night nodded, but rumbled a warning to his subordinates. “Horror, remember that I’m his primary mate, and that you get to feed him up - he’s thinner than he should be. He already ate most of the food you had pre-made this last week!”

Blue blushed. “It was very good, Horror. I can’t wait to try more of it!”

Horror stood, blushing a dark blue back at them. “aw, yer makin me blush! i promise i’ll be good, boss. you let me keep my brother and lust away from this pack so i didn’t have to share and they didn’t feel used. i’ll take care of your mate, too.”

Killer grinned. “so you said yes, huh blue? can’t blame ya. m’a beta, and boss knows how to take care of his mate good. he didn’t get the whole alpha at first, but i helped him learn.”

Blue’s eyes snapped up to Nightmare, who was blushing. “The black apples seemed to have changed my secondary gender. I used to be an Omega like you… and I used to be treated by the villagers the same way you’ve been treated by the monsters of your world. I know how it feels to be treated like a toy. I hate the fact that it happened to you.”

Blue, impulsively, kissed him. His tentacles formed little hearts when he was happy - like right now. “I won’t be anymore, though, and… maybe I can get Dream and Ink to let you do something about other worlds where it happens. Dream tries, but bribery only works so far.”

Nightmare smiled a very wicked smile. Blue would bet any amount of money that he was imagining what he would do to people who did that. Blue would have felt more sympathy if he didn’t know firsthand what that treatment could do to someone, especially an Omega, who endured it for too long.

He was so focused on Nightmare’s face that he didn’t hear Horror and Killer coming until they touched him. He started, then saw it was just them touching his hands. He relaxed and blushed. With one last look at his primary mate he said, “How would you like to take me?”

Horror grinned at Killer over Blue’s shoulder. “killer here likes the ass if you’re okay with it. i’m a mouth guy. cross is huge into boobs, and slayer can take your pussy. that good with you?”

Blue felt his tongue fall out and let it stay there. Oh, stars, that sounded good. “Yes, please!”

Grins sprouted around him. “Then I’ll prep you while they get themselves ready,” Nightmare said. A now-familiar squirt of lube from behind him was quickly followed by tentacles feeling up all of his holes, smearing him with that heavenly substance that turned unwelcome pain into pleasurable friction. His holes didn’t need to be stretched, though, because Nightmare had been stretching them all week. “Are you ready, little Blue?” 

The Omega nodded. “Please, pack, fill me up!”

He didn’t need to say anything else. Nightmare lowered him on his back over Killer, who slipped inside with ease and a groan. Horror’s thrust was faster, burying his dick up to the knot in Blue’s mouth. He moaned around it when Cross straddled him and used his pendulous breasts to cup his cock. Blue’s breasts were very sensitive. Slayer’s slide into his pussy came as an overwhelming relief. He had a pack; he was going to please them. It felt good.

That was all the thought he had for some time. Getting fucked in four “holes” at one was mind numbing. If that weren’t enough, Nightmare was stroking his thin, scarred stomach with his tentacles. He quickly lost track of all sensations individually. All he knew was the pleasure he was feeling.

Horror gripped Blue’s head gingerly and slipped his knot in first. His cum tasted like pork blood sausage. Blue let him cum as the others kept fucking him. His knot was thick, but Blue had taken thicker.

The next one to cum was Cross. He came just after Horror pulled out of his mouth, so Blue was able to taste his cum, too. Cross tasted like chocolate milk and tortillas, an odd combination that fit what Blue knew about him. He hoped Horror wouldn’t mind if he used his kitchen to make some tacos for Cross sometime. Cross deserved it. 

After Cross was Slayer. He came with a cry that was so sweet sounding. Blue reached a hand up to take one of Slayer’s and asked him, “Can you scoop a little of your cum out of me when your knot deflates? I want to know what my whole pack tastes like.” Slayer, blushing, nodded.

Killer held out until the very end, then stuck his knot in and wrapped his arms around Blue. “i’ll save some for you, too. i like knowing how everyone tastes, too~” He purred. 

Blue giggled, then hesitated. Quietly, he asked, “Can I… make puns now, too?”

All of the eye lights that he could see sparkled like stars. “You like puns?” They all asked him simultaneously.

Blue nodded. “I do, but Stretch doesn’t, so I don’t tell them.”

“Well, you can tell your new pack as many puns as you want, Blue, because we love them. What’s your pun?” Nightmare demanded.

Blue gulped nervously, debated whether it was worth it if they didn’t like it, then said, “You could say that knowing the flavor of your pack makes you feel cum-plete!” When they all burst into laughter, he couldn’t help but join in, “Mweh heh heh!”

The starry eyes returned, and Killer said, “wow. we really are the luckiest pack in the multiverse.”

Nightmare kissed Blue deeply, then said, “Yes. Yes we are.”

**Author's Note:**

> You can find me on:
> 
> Pillowfort - https://www.pillowfort.social/Yastaghr  
> Tumblr - https://yastaghr.tumblr.com  
> Twitter - https://twitter.com/yastaghr * Most active


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